Engine oil feeding device

ABSTRACT

An engine oil feeding device is provided, which includes a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, and for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change its discharging amount, an oil supply channel communicating with the operating chamber and coupled to an oil fed part, and an oil filter. The oil supply channel includes a pump downstream oil channel connecting the operating chamber with the filter and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber. The device also includes a control valve provided in the control oil channel. A starting control is performed in which the valve opening is set larger than a predetermined rate before the pump starts driving and set smaller than the predetermined rate after the pump starts driving.

TECHNICAL FIELD

The technology disclosed herein relates to an engine oil feeding device.

BACKGROUND

Conventionally, oil is supplied to lubricating parts, such as a hydraulically operating device of an engine (e.g., a variable valve timing mechanism) and an engine crankshaft, through a hydraulic path by a variable-displacement oil pump. Since the oil pump is a variable displacement type, unnecessary driving of the oil pump is avoided and fuel consumption is improved.

For example, JP2013-130089A discloses a pump that brings a pump discharging pressure close to a required oil pressure to reduce power loss.

According to JP2013-130089A, when an engine runs at a high speed, an electromagnetic changeover valve leads the oil pressure to a second control oil chamber through first and second solenoid control ports having an orifice effect. Meanwhile, at an initial position where a first spool valve is biased by a first valve spring to be moved fully rightward, a pilot valve shuts off a communicating state between an oil-pressure introduction port and a first pilot control port. Then, when a discharging pressure increases, both ports are made to be in the communicating state, and a second pilot control port and a first drain port are made to be in the communicating state to control an oil pressure of a first control oil chamber. When maintaining a desired discharging pressure is demanded, an excessive rise of the discharging pressure is controlled even if a pump rotational speed increases.

In the meantime, especially at an engine start under a low ambient temperature environment, the viscosity of the oil is high and the variable-displacement oil pump is in its maximum displacement state. Thus, an abnormally high oil pressure may be applied to an oil filter and may damage the filter.

In order to solve such a problem, as illustrated in FIG. 13, a leak passage 900 is conventionally provided between an oil pump 36 and an oil filter 37 disposed downstream of the oil pump 36, and excessive oil is leaked into an oil pan 6 through the leak passage 900. However, it is necessary to attach a check valve 901 to the leak passage 900, resulting in a complicated structure.

SUMMARY

The technology disclosed herein is made in view of the above issues, and the purpose thereof is to provide an oil feeding device which prevents damage to an oil filter with a simple configuration.

To achieve the above purpose, in this disclosure, a branch passage is provided between an operating chamber of an oil pump and an oil filter, and this branch passage is directly coupled to a control oil-pressure chamber of the oil pump through a control valve. When the oil pump starts driving at an engine start, the valve opening of the control valve is set larger than a predetermined rate so as to increase an oil flow rate to the branch passage, resulting in avoiding oil with high viscosity flowing into the oil filter in large quantities.

That is, an engine oil feeding device disclosed herein includes a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof, an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump, and an oil filter disposed in the oil supply channel. The oil supply channel includes a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter, and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump. The device also includes a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by a valve opening thereof being changed. A starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate before the oil pump starts driving and set smaller than the predetermined rate after the oil pump starts driving.

As described above, a leak passage is conventionally provided between an operating chamber of an oil pump and an oil filter and excessive oil is leaked into an oil pan. However, it is necessary to attach a check valve to the leak passage in the conventional structure, resulting in a complicated structure.

According to this technology, the control oil channel is provided between the operating chamber of the oil pump and the oil filter, and this control oil channel is coupled to the control oil-pressure chamber of the oil pump through the control valve. Thus, the excessive oil is directly introducible into the control oil-pressure chamber of the oil pump without leaking to the oil pan, and the pump work is reduced. Further, when the oil pump starts driving at the engine start, the controller controls, based on the starting demand of one of the engine and the oil pump, the control valve to open more than a predetermined rate so that oil is able to circulate in the control oil channel. Thus, when the oil pump starts driving, the high-viscosity oil avoids flowing into the oil filter so as to prevent damage to the oil filter.

In addition, an engine oil feeding device disclosed herein includes a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof, an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump, and an oil filter disposed downstream of the operating chamber of the oil pump in the oil supply channel. The oil supply channel includes a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter, and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump. The device also includes a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by a valve opening thereof being changed, and a fluid temperature detector mounted to one of the engine and a component of a vehicle to which the engine is mounted, and for detecting temperature of fluid that contacts one of the engine and the component. A starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate when a fluid temperature detection value detected by the fluid temperature detector is below a predetermined value before the oil pump starts driving and the valve opening is set smaller than the predetermined rate after the oil pump starts driving.

Here, in the specification, “one of the engine and a component of a vehicle to which the engine is mounted” means the engine, the component parts, structures, etc. constituting the engine, and the component parts, structures, etc. constituting the vehicle onto which the engine is mounted and includes, for example, an oil supply channel, a cylinder head, a water jacket, exterior components such as a vehicle door, or an exhaust passage of the engine. In addition, “fluid that contacts one of the engine and the component of the vehicle” means the fluid that contacts one of the engine and at least one of the inner surface and the outer surface of the component constituting the vehicle and includes, for example, a coolant in the water jacket formed to the cylinder head, air which contacts the exterior components such as a vehicle door, or exhaust gas passing through the exhaust passage of the engine.

When the temperature of the fluid that contacts one of the engine and the component of the vehicle as described above is low, the viscosity of oil is considered to be high. Therefore, according to this technology, the temperature of the fluid that contacts the component of the vehicle is detected, and when the detected oil temperature is below the predetermined value, the oil flow rate of the control oil channel is increased to be above a predetermined rate. Thus, the oil flow rate flowing into the oil filter is reduced so as to prevent damage to the oil filter.

In addition, an engine oil feeding device disclosed herein includes a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof, an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump, and an oil filter disposed downstream of the operating chamber of the oil pump in the oil supply channel. The oil supply channel includes a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter, and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump. The device also includes a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by a valve opening thereof being changed, and a fluid temperature detector mounted to one of the engine and a component of a vehicle to which the engine is mounted, for detecting temperature of fluid that contacts one of the engine and the component. A starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate when an estimated viscosity value estimated based on a fluid temperature detection value detected by the fluid temperature detector is above a predetermined value before the oil pump starts driving, and the valve opening is set smaller than the predetermined rate after the oil pump starts driving.

According to this technology, the temperature of the fluid that contacts the component of the vehicle is detected, and the viscosity of the oil is estimated based on the detected fluid temperature detection value and the relation of the fluid temperature and the viscosity of oil stored in the memory. When the estimated viscosity value is above the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

The fluid may be oil flowing through the pump downstream oil channel. The fluid temperature detector may detect an oil temperature upstream of the oil filter.

According to this technology, the oil temperature before flowing into the oil filter is detected. When the detected oil temperature is below the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

Further, the oil temperature is detected and the viscosity of the oil is estimated based on the detected oil temperature detection value, and the relation of the oil temperature and the oil viscosity stored in the memory. When the estimated viscosity value is above the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

The fluid may be a coolant that flows in a water-cooled part of the engine. The fluid temperature detector may detect a coolant temperature of the coolant in the water-cooled part.

According to this technology, the coolant temperature of the coolant in the water-cooled part of the engine (e.g., the water jacket of the cylinder head) is detected. When the detected coolant temperature is below the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

Further, the coolant temperature is detected and the viscosity of the oil is estimated based on the detected coolant temperature detection value and the relation of the coolant temperature of coolant and the oil viscosity stored in the memory. When the estimated viscosity value is above the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

The fluid may be air outside of the vehicle. The fluid temperature detector may detect an ambient temperature outside the vehicle.

According to this technology, the temperature of the air which contacts the exterior component of the vehicle (e.g., the vehicle door), i.e., the ambient temperature, is detected. When the detected ambient temperature is below the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

Further, the ambient temperature is detected and the viscosity of the oil is estimated based on the detected ambient temperature detection value, and the relation of the ambient temperature and the oil viscosity stored in the memory. When the estimated viscosity value is above the predetermined value, the oil flow rate of the control oil channel is increased to be above the predetermined rate, which results in reducing the oil flow rate flowing into the oil filter and preventing damage to the oil filter.

The controller may set the valve opening of the control valve to the maximum rate in the starting control.

When the oil pump starts driving at the engine start, generally the oil temperature is low and the viscosity of the oil may be high. If such a low-temperature, high-viscosity oil flows into the oil filter in large quantities, the filter may be damaged.

According to this technology, the valve opening of the control valve is set to the maximum rate and the oil flow rate of the control oil channel is set to the maximum rate when the oil pump starts driving at the engine start, which results in avoiding the low-temperature, high-viscosity oil flowing into the oil filter when the oil pump starts driving, thereby preventing damage to the oil filter.

The oil pump may be provided with a pump housing accommodating the operating chamber and having a discharge port for discharging the oil from the operating chamber. The pump downstream oil channel may be provided in the pump housing and having a discharge passage connecting the operating chamber with the discharge port. The control oil channel may be branched from the discharge passage, and the control oil channel and the control valve may be integrally formed with the pump housing.

According to this technology, by integrally forming the control oil channel and the control valve with the pump housing, downsizing of the oil feeding device is achieved. Moreover, since the oil channel length of the control oil channel is shorter than the case where the control oil channel is formed in other engine parts, the pump work is reduced.

The oil supply channel may have a hydraulic path communicating with a downstream side of the oil filter and connected with the oil fed part. The engine oil feeding device may further include an oil-pressure detector for detecting an oil pressure of the hydraulic path. In a case where a detection value of the oil-pressure detector becomes above a predetermined value during the starting control, the control of the control valve is switched to a feedback control in which the valve opening of the control valve is adjusted so that the oil pressure of the hydraulic path becomes a target oil pressure that is determined according to an operating state of the engine

As illustrated in FIG. 13, in the conventional oil feeding device, a feedback control is performed though a feedback control oil channel 40 branched at a branched point 54 b of a hydraulic path communicating with a downstream side of the oil filter and connected with the control valve. According to this technology, the control oil channel branched from the pump downstream oil channel also functions as the hydraulic path for the feedback control, and the control valve also functions as a hydraulic control valve for the feedback control, resulting in further downsizing of the oil pump. Moreover, as described above, for a while after the oil pump starts driving at the engine start, the viscosity of the oil is high, and thus it may cause damage to the oil filter.

According to this technology, after the engine start, until the oil pressure detection value exceeds the predetermined value, the starting control is performed to prevent damage of the oil filter. After the oil pressure detection value exceeds the predetermined value, since the viscosity of the oil decreases and the possibility of damaging the oil filter is reduced, the control is switched to the normal feedback control of the oil pump so that the oil pressure of the hydraulic path is controlled efficiently. Further, in a case where the starting control is not performed, since the normal feedback control is performed from when the oil pump starts driving at the engine start, the oil pressure of the hydraulic path is controlled efficiently.

The oil supply channel may have a hydraulic path communicating with a downstream side of the oil filter, and connected with the oil fed part. The engine oil feeding device may further include an engine speed detector for detecting an engine speed of the engine. In a case where an engine speed detection value detected by the engine speed detector becomes above a predetermined engine speed during the starting control, the control of the control valve is switched to a feedback control in which the valve opening of the control valve is adjusted so that an oil pressure of the hydraulic path becomes a target oil pressure.

According to this technology, until the engine speed becomes the predetermined engine speed, the starting control is performed to prevent the damage of the oil filter. After the engine speed becomes the predetermined engine speed, the control is switched to the normal feedback control of the oil pump so that the oil pressure of the hydraulic path is controlled efficiently. Further, in a case where the starting control is not performed, since the normal feedback control is performed from when the oil pump starts driving at the engine start, the oil pressure of the hydraulic path is controlled efficiently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view schematically illustrating a configuration of a multi-cylinder engine to which an oil feeding device according to a first embodiment is applied.

FIG. 2 is a view schematically illustrating a configuration of a hydraulic system.

FIG. 3 is a cross-sectional perspective view schematically illustrating a state where a cover member is removed from a variable-displacement oil pump.

FIG. 4 is a front view schematically illustrating the variable-displacement oil pump of FIG. 3.

FIG. 5 is a cross-sectional view taken along a line A-A of FIG. 4.

FIG. 6 is a cross-sectional view taken along a line B-B of FIG. 5.

FIG. 7 is a cross-sectional view taken along a line C-C of FIG. 3.

FIG. 8 is a cross-sectional view schematically illustrating an internal structure of an oil control valve in FIG. 7.

FIG. 9 is a flowchart illustrating a control flow of the hydraulic system according to the first embodiment.

FIG. 10 is a graph illustrating changes with time of the oil pressures of the oil supply channels of the hydraulic system according to the first embodiment and a conventional hydraulic system, and an engine speed.

FIG. 11 is a flowchart illustrating a control flow of a hydraulic system according to a second embodiment.

FIG. 12 is a flowchart illustrating a control flow of a hydraulic system according to a fifth embodiment.

FIG. 13 is a view schematically illustrating a configuration of the hydraulic system provided with a conventional oil feeding device.

DETAILED DESCRIPTION

Hereinafter, several embodiments of the present technology are described in detail with reference to the accompanying drawings. The following description of desirable embodiments is essentially only an illustration and is not intended to limit the present technology, nor its application or usage.

First Embodiment <Hydraulic System> [Engine Configuration]

FIG. 1 illustrates a multi-cylinder engine 2 (hereinafter, simply referred to as “the engine 2”) to which an oil feeding device according to this embodiment is applied. The engine 2 is an in-line four-cylinder gasoline engine in which first to fourth cylinders are disposed in line in a direction perpendicular to a drawing surface of FIG. 1 in this order, and is mounted on a vehicle, such as a four-wheel automobile. In the engine 2, a cam cap 3, a cylinder head 4, a cylinder block 5, a crankcase (not illustrated), and an oil pan 6 (see FIG. 2) are coupled vertically. Pistons 8 which are slidable inside four cylinder bores 7 formed in the cylinder block 5, respectively, are coupled via connecting rods 10 to the crankshaft 9 which is rotatably supported by the crankcase, and the cylinder bores 7 of the cylinder block 5, the pistons 8, and the cylinder head 4 form combustion chambers 11 for cylinders, respectively.

The cylinder head 4 is provided with an intake port 12 and an exhaust port 13 which open to each combustion chamber 11, and each pair of the ports 12 and 13 is provided with an intake valve 14 and an exhaust valve 15 which open and close the intake port 12 and the exhaust port 13, respectively. The intake valve 14 and the exhaust valve 15 are biased in a closed direction (upward in FIG. 1) by return springs 16 and 17, respectively. Cam parts 18 a and 19 a formed on cam shafts 18 and 19 which are rotating push downwardly cam followers 20 a and 21 a rotatably provided in substantially center parts of swing arms 20 and 21, respectively. The swing arms 20 and 21 swing around top parts of pivot mechanisms provided at one end side of the swing arms 20 and 21 to push the intake valve 14 and the exhaust valve 15 downwardly at the other end of the swing arms 20 and 21 so as to resist biasing forces of the return springs 16 and 17, and thus, the intake valve 14 and the exhaust valve 15 are opened.

[Hydraulically Operating Device]

The engine 2 is provided with various hydraulically operating devices (oil fed part) which are operated by hydraulic pressure of the oil supplied from an engine oil feeding device according to this embodiment.

For example, as the pivot mechanisms (the same configuration as a pivot mechanism of a HLA 25 described later) of the swing arms 20 and 21 of the second and third cylinders located in a center part of the engine 2 in the cylinder line-up direction, well-known hydraulic lash adjusters (hereinafter, referred to as “HLA” which is an abbreviation thereof) which automatically and hydraulically adjust valve clearances to zero are provided (not illustrated in detail).

Moreover, for the swing arms 20 and 21 of the first and fourth cylinders located at both end parts in the cylinder line-up direction, HLAs 25 with a valve stop mechanism provided with a pivot mechanism are provided. Although a detailed illustration is omitted, the HLAs 25 have, in addition to the pivot mechanism configured to be automatically adjustable of the valve clearance to zero similar to the unillustrated HLA, the valve stop mechanism which stops operation (stops opening-and-closing operation) of the intake and exhaust valves 14 and 15 of the first and fourth cylinders during a reduced-cylinder operation in which operation of some of the cylinders (corresponding to specific cylinder(s)) is stopped, while resuming the operation of the intake and exhaust valves 14 and 15 of the first and fourth cylinders (the opening-and-closing operation is performed) during an all-cylinder operation in which all the cylinders (four cylinders) are operated. The intake and exhaust valves 14 and 15 of the second and third cylinders operate both during the reduced-cylinder operation and the all-cylinder operation. For this reason, during the reduced-cylinder operation, the intake and exhaust valves 14 and 15 of the first and fourth cylinders among all the cylinders of the engine 2 stop their operations, and the intake and exhaust valves 14 and 15 of all the cylinders operate during the all-cylinder operation. Note that the reduced-cylinder operation and the all-cylinder operation are switched according to an operating state of the engine 2.

Mounting holes 26 and 27 are formed in portions of the cylinder head 4 on the intake and exhaust sides corresponding to the first and fourth cylinders, respectively. Lower end parts of the HLAs 25 with the valve stop mechanism are inserted and mounted into the mounting holes 26 and 27. Similarly to the mounting holes 26 and 27, mounting holes are formed in portions of the cylinder head 4 on the intake and exhaust sides corresponding to the second and third cylinders, respectively, and lower end parts of the HLAs 24 are inserted and mounted thereinto. Further, two pairs of the oil channels 61 and 63, 62 and 64 are formed in the cylinder head 4, which communicate with the mounting holes 26 and 27 for the HLAs 25, respectively. In a state where the HLAs 25 are fitted into the mounting holes 26 and 27, the oil channels 61 and 62 supply oil pressure (hydraulic pressure) to operate the valve stop mechanisms of the HLAs 25, and the oil channels 63 and 64 supply oil pressure to cause the pivot mechanisms of the HLAs 25 to automatically adjust the valve clearances to zero. Note that only the oil channels 63 and 64 communicate with the mounting holes for the HLAs 24.

A main gallery 54 is formed inside a side wall of the cylinder block 5 on the exhaust side of the cylinder bores 7 so as to extend in the cylinder line-up direction. An oil jet 28 (oil injection valve) is formed, for every piston 8, near the bottom of the main gallery 54 so as to communicate with the main gallery 54 and cool the corresponding piston 8. The oil jet 28 has a nozzle part 28 a disposed below the piston 8, and injects engine oil (hereinafter, simply referred to as “the oil”) from the nozzle part 28 a toward the back side of a top part of the piston 8.

Oil showers 29 and 30 comprised of pipes are provided above the cam shafts 18 and 19, respectively. Lubricating oil is configured to be dropped from the oil showers 29 and 30 onto the cam parts 18 a and 19 a of the cam shafts 18 and of 19 located below the oil showers 29 and 30, and onto contacting parts between the swing arms 20 and 21 and the cam followers 20 a and 21 a which are located further below.

Although not illustrated in FIG. 1, a variable valve timing mechanism (hereinafter, simply referred to as “the VVT”) as a hydraulically-operating valve characteristic changing device is provided to change, by hydraulic operation, valve characteristic(s) of at least one (both in this embodiment) of the intake valve 14 and the exhaust valve 15 of every cylinder of the engine 2. There are an exhaust side VVT and an intake side VVT. Both the intake side VVT and the exhaust side VVT are hydraulically operating devices, similar to the HLAs 24 and 25, and since the configurations are well-known, description thereof is omitted. However, the intake side VVT and the exhaust side VVT supply and discharge the oil pressure to an advance oil-pressure chamber and a retard oil-pressure chamber on the intake and exhaust sides, respectively, to shift rotation phases of the cam shafts 18 and 19 with respect to a rotation phase of the crankshaft 9 so that valve-opening phases of the intake valve 14 and the exhaust valve 15 are changed between the advancing direction and the retarding direction.

[Hydraulic System]

Next, a hydraulic system 1 (oil feeding device) described above for supplying oil to the engine 2 is described with reference to FIGS. 1 and 2. The hydraulic system 1 includes a variable-displacement oil pump 36 (hereinafter, referred to as “the oil pump 36”) driven by the rotation of the crankshaft 9, and an oil supply channel H coupled to the oil pump 36.

[Oil Pump]

The oil pump 36 is auxiliary machinery driven by the engine 2. The oil of which the pressure is increased by the oil pump 36 is led to the lubricating parts and the hydraulically operating devices of the engine 2 through the oil supply channel H.

As illustrated in FIGS. 3 and 4, the oil pump 36 is a variable-displacement oil pump which changes the displacement thereof to vary an oil discharging amount. The oil pump 36 includes a housing 361 (pump housing) comprised of a pump body having a pump accommodating chamber which is formed so as to open at one end side and inside of which is a space having a circular cross-section, and a cover member which blocks the opening at one end side of the pump body. The oil pump 36 also includes a drive shaft 362 which is rotatably supported by the housing 361, penetrates a substantially center part of the pump accommodating chamber, and is rotated by the crankshaft 9. The oil pump 36 also includes a pump component comprised of a rotor 363 which is rotatably accommodated inside the pump accommodating chamber and of which a center part is coupled to the drive shaft 362, and vanes 364 accommodated respectively in a plurality of slits which are radially formed by notching an outer circumferential part of the rotor 363 so that the vanes 364 appear from and retract into the slits. The oil pump 36 also includes a cam ring 366 which is disposed at the outer circumferential side of the pump component so as to be eccentric with respect to a rotation center of the rotor 363, and defines a plurality of pump chambers 365 (operating chambers) together with the rotor 363 and the adjacent vanes 364. The oil pump 36 also includes a spring 367 which is accommodated in the pump body and is a biasing member which always biases the cam ring 366 to a side which increases the eccentricity of the cam ring 366 with respect to the rotation center of the rotor 363. The oil pump 36 also includes a pair of ring members which are slidably disposed at both side parts on the inner circumference side of the rotor 363 and are smaller in the diameter than the rotor 363.

The housing 361 includes a suction passage 361 a through which the oil is supplied to the pump chamber 365 accommodated inside the housing 361, a suction port 361 a′ of the suction passage 361 a at an opening end opposite from the pump chamber, a discharge passage 361 b (pump downstream oil channel) through which the oil is discharged from the pump chamber 365, and a discharge port 361 b′ of the discharge passage 361 b at an opening end opposite from the pump chamber.

Inside the housing 361, a pressure chamber 369 (control oil-pressure chamber) defined by an inner circumferential surface of the housing 361, an outer circumferential surface of the cam ring 366, and a seal part 370 which contacts these surfaces is formed, and an introduction hole 369 a which opens to the pressure chamber 369 is formed.

The oil pump 36 introduces the oil into the pressure chamber 369 from the introduction hole 369 a, the cam ring 366 swings about a fulcrum 361 c, and the rotor 363 becomes eccentric relative to the cam ring 366, to change the discharging amount of the oil pump 36. That is, the discharging amount is configured to be changeable by changing the displacement of the pump chamber 365 according to the pressure inside the pressure chamber 369.

An oil strainer 39 which faces to the oil pan 6 is connected to the suction port 361 a′ of the oil pump 36. Moreover, an oil cooler 38 is disposed in a second oil channel 51 downstream of the oil filter 37. The oil which is reserved inside the oil pan 6 is pumped up by the oil pump 36 through the oil strainer 39, and is filtered by the oil filter 37 and cooled by the oil cooler 38. The oil is then introduced into the main gallery 54 inside the cylinder block 5, and into a head gallery 60 inside the cylinder head 4.

The oil for lubrication and cooling is supplied to metal bearings which rotatably support the crankshaft 9 and the cam shafts 18 and 19, the piston 8, the cam shafts 18 and 19, etc. The oil after cooling and lubrication is dropped into the oil pan 6 passing through a drain oil channel (not illustrated), and again circulates by the oil pump 36.

[Oil Supply Channel]

The oil supply channel H communicates with the pump chamber 365 of the oil pump 36, and is connected to the lubricating parts and the hydraulically operating devices of the engine 2. The oil filter 37 is disposed in the oil supply channel H, downstream of the pump chamber of the oil pump 36.

The oil supply channel H includes a first oil channel 93 (pump downstream oil channel) which connects the discharge port 361 b′ of the oil pump 36 to the oil filter 37, and a hydraulic path 50 connected to a downstream side of the oil filter 37.

Note that the pump downstream oil channel connecting the pump chamber 365 of the oil pump 36 to the oil filter 37 is comprised of the first oil channel 93, and the discharge passage 361 b (pump downstream oil channel) provided to the housing 361 of the oil pump 36.

The hydraulic path 50 is comprised of, for example, piping and/or passages formed in the cylinder head 4 and the cylinder block 5. Specifically, the hydraulic path 50 includes the second oil channel 51 extending from the oil filter 37 to a branched point 54 b in the cylinder block 5, and the main gallery 54 extending in the cylinder line-up direction inside the cylinder block 5. The hydraulic path 50 also includes a third oil channel 52 extending from the branched point 54 b to the cylinder head 4, and the head gallery 60. The head gallery 60 is comprised of a fourth oil channel extending to a substantially horizontal direction between the intake side and the exhaust side inside the cylinder head 4, and a plurality of the oil channels 61-64 which branch from the fourth oil channel inside the cylinder head 4.

The main gallery 54 is connected to the oil jets 28 for injecting the oil for cooling to the back sides of the four pistons 8, a lubricating part (oil fed part; not illustrated) of the metal bearings disposed at five main journals which rotatably support the crankshaft 9, and a lubricating part ((oil fed part) not illustrated) of the metal bearings disposed at crankpins of the crankshaft 9 to which four connecting rods are rotatably coupled. The oil is constantly supplied to the main gallery 54.

An oil-pressure sensor 70 (oil-pressure detector) for the hydraulic path is disposed in the main gallery 54, which detects oil pressure of the main gallery 54. The oil-pressure sensor 70 is configured to detect the oil pressure of the hydraulic path 50 for supplying the oil to the lubricating parts and the hydraulically operating devices of the engine 2 by the oil pump 36. Note that, in addition to the oil-pressure sensor 70, the hydraulic system 1 is provided with a plurality of the oil-pressure sensors, for example, on the perimeter of the hydraulically operating devices inside the main gallery 54, the head gallery 60, etc., and the plurality of the oil-pressure sensors detect the oil pressure of the hydraulic path 50.

Since the head gallery 60 has similar configurations on the exhaust and intake sides, the exhaust side is described as an example. For example, an oil channel 60A of the head gallery 60 is connected with the advance oil-pressure chamber and the retard oil-pressure chamber of the exhaust-side VVT for changing the opening-and-closing timing of the exhaust valve 15 through an exhaust-side first direction changeover valve, and the oil is supplied by controlling the first direction changeover valve. The oil channel 64 is connected to a lubricating part (oil fed part; not illustrated) of the metal bearings disposed in the cam journals of the cam shaft 19 on the exhaust side and the HLA 25 with the valve stop mechanism. Further, an oil channel 60B of the head gallery 60 is connected to the oil shower 30 which supplies the lubricating oil to the exhaust-side swing arm 21.

An oil channel 60C of the head gallery 60 branches to two oil channels 61 and 62 which communicate with the HLAs 25. The oil channels 61 and 62 are connected with the valve stop mechanisms of the HLAs 25 on the intake and exhaust sides through the second direction changeover valves on the intake and exhaust sides, respectively, and the oil is supplied to each valve stop mechanism by controlling these second direction changeover valves.

<Features of Hydraulic System>

Here, the hydraulic system 1 according to this embodiment has such a feature that the system includes a control oil channel 90 that is branched from the discharge passage 361 b as the pump downstream oil channel and is connected to the pressure chamber 369 of the oil pump 36.

An oil control valve 49 (control valve) is provided to the control oil channel 90, which is changeable of an oil flow rate of the control oil channel 90 by changing a valve opening of the valve. The control oil channel 90 and the oil control valve 49 are integrally formed with the housing 361 of the oil pump 36.

The control oil channel 90 and the oil control valve 49 are used for a starting control SA described later when the oil-pump is actuated at a startup of the engine 2, and a normal control SB (feedback control) described later at a normal operation of the engine 2. Hereinafter, each configuration is described in detail.

[Control Oil Channel]

As illustrated in FIGS. 5 and 6, an upstream control oil channel 90 a of the control oil channel 90 branches from the discharge passage 361 b of the housing 361 and is connected to the oil control valve 49 which is integrally formed with the housing 361.

The oil, which is sent out to the discharge passage 361 b from the pump chamber 365 of the oil pump 36 and is introduced into the oil control valve 49 through the upstream control oil channel 90 a, passes through the oil control valve 49, and as illustrated in FIG. 2, is then introduced into the pressure chamber 369 of the oil pump 36 through a downstream control oil channel 90 b of the control oil channel 90. As illustrated in FIG. 7, the downstream control oil channel 90 b is connected with the pressure chamber 369 of the oil pump 36 through the oil channel formed by a valve housing 496 and a spool valve 491 of the oil control valve 49.

That is, in this embodiment, the control oil channel 90 functions as a leak passage for damage prevention of the oil filter 37 when the starting control SA is performed, and functions as a passage for controlling the oil discharging amount of the oil pump 36 when the normal control SB is performed. Since the leak passage and the control passage are commonly formable by having the configuration described above, the oil pump 36, i.e., the hydraulic system 1 is downsizable.

[Oil Control Valve]

As illustrated in FIG. 8, the oil control valve 49 includes the valve housing 496, the spool valve 491 accommodated inside the valve housing 496, a filter 494 which is formed in the valve housing 496 and filters the oil, an electromagnetic coil 493 which generates an electromagnetic force, a plunger 495 which displaces the spool valve 491 in directions of an arrow 497 by the electromagnetic force of the coil 493, and a valve spring 492. The spool valve moves in the directions of the arrow 497 to change a valve opening of the oil channel of the oil control valve 49. Thus, a channel cross-sectional area of the oil introduced from the upstream control oil channel 90 a is changed, and a passing flow rate of the oil is changed.

Note that the oil control valve 49 is not limited to the configuration described above, but an electromagnetic control valve having a well-known configuration is suitably used.

[IG-ON/OFF Detector]

As illustrated in FIG. 2, the hydraulic system 1 according to this embodiment is provided with an ignition ON/OFF detector 105 (hereinafter, referred to as “the IG-ON/OFF detector”) as a starting demand detector which detects an ON signal of an ignition switch at a startup of the engine 2 (a starting demand). Note that instead of the starting demand of the engine 2, a starting demand of the oil pump 36 may be detected.

[Oil-Temperature Detector]

As illustrated in FIG. 2, on the first oil channel 93, an oil temperature detector (fluid temperature detector) 92 to detect the oil temperature upstream of the oil filter 37 is disposed. Note that the oil temperature detector 92 may also be installed on the discharge passage 361 b of the oil pump 36 (e.g., may be disposed in the housing 361 so as to detect oil temperature inside the discharge passage 361 b).

[Control Unit]

As illustrated in FIG. 2, a control unit 100 (controller) is a control device which uses a well-known microcomputer as a base component, and detects the operating state of the engine 2 from the detected information inputted from various sensors, such as the oil-pressure sensor 70, the oil temperature detector 92, an engine speed detector 102, an accelerator opening detector 103, a gear detector 104, and the IG-ON/OFF detector 105, and outputs the control signals to the devices to be controlled, such as the oil control valve 49. Operation of the engine 2 is controlled by the control unit 100.

The control unit 100 supplies a control signal of a duty ratio to the oil control valve 49 and controls the valve opening of the oil control valve 49 to adjust the passing flow rate, and through which the oil pressure supplied to the pressure chamber 369 of the oil pump 36 is controlled. This oil pressure of the pressure chamber 369 controls the eccentricity of the cam ring 366 to control an amount of change of the internal displacement of the pump chamber 365, resulting in the flow rate (the discharging amount) of the oil pump 36 being controlled. Here, since the oil pump 36 is driven by the crankshaft 9 of the engine 2, the flow rate (the discharging amount) of the oil pump 36 is proportional to an engine speed.

Thus, the control unit 100 constitutes a controller which changes the capacity of the oil pump 36 to control the discharging amount of the oil pump 36.

[Normal Control]

The hydraulic system 1 supplies the oil to the plurality of lubricating parts and hydraulically operating devices by a single oil pump 36, and a demanded oil pressure required for each of the lubricating parts and hydraulically operating devices varies according to the operating state of the engine 2. Thus, in order to obtain the oil pressure required for all the lubricating parts and hydraulically operating devices in all the operating states of the engine 2, the oil pump 36 needs to set an oil pressure higher than the highest demanded oil pressure among the demanded oil pressures of the hydraulically operating devices as a target oil pressure for every operating state of the engine 2. For this purpose, each target oil pressure is set so as to satisfy the demanded oil pressures of the valve stop mechanism, the oil jet 28, the metal bearing, such as the journal of the crankshaft 9, the intake side VVT, and the exhaust-side VVT, of which the demanded oil pressures are comparatively high among all the lubricating parts and hydraulically operating devices. Therefore, if the target oil pressures are set in this way, the target oil pressures naturally satisfy the demanded oil pressures of other hydraulically operating devices which are comparatively lower.

The target oil pressures for every operating state of the engine 2 are temporary determined based on the highest demanded oil pressure among the demanded oil pressures of the intake side VVT, the exhaust side VVT, the metal bearing, and the oil jet 28, and the temporary target oil pressures are set beforehand to the oil-pressure control map and stored in the memory 100 d of the control unit 100. The control unit 100 reads out the temporary target oil pressure according to the operating state of the engine 2 from the oil-pressure control map, and then sets one of the read-out temporary target oil pressure and the demanded oil pressure of the valve stop mechanism of the HLA 25 which is higher than the other, as the target oil pressure. The control unit 100 reads an oil pressure (actual oil pressure) detected by the corresponding oil-pressure sensor, and executes an oil-pressure feedback control in which the discharging amount of the oil pump 36 is controlled as the normal control SB by adjusting the valve opening of the oil control valve 49 so that the actual oil pressure reaches the target oil pressure.

[Starting Control]

When the ON signal is detected by the IG-ON/OFF detector 105, the control unit 100 reads an oil-temperature detection value (a fluid temperature detection value) detected by the oil temperature detector 92 before driving of the oil pump 36 is started. If the oil-temperature detection value detected by the oil temperature detector 92 is below a predetermined value, the control unit 100 performs the starting control SA in which the valve opening of the oil control valve 49 is set larger than a predetermined rate so that the oil is possible to circulate through the control oil channel 90.

On the other hand, if the oil-temperature detection value detected by the oil temperature detector 92 exceeds the predetermined value, the control unit 100 does not perform the starting control SA.

The starting control SA is required when the ambient temperature is at an extremely low temperature, and when at such an ambient temperature, the temperature of the engine oil is substantially the same temperature as the ambient temperature and thus, the oil viscosity is relatively high. Specifically, for example, the starting control SA is performed when the oil temperature detected by the oil temperature detector 92 is less than −10° C.

Thus, in the case of the low-temperature high-viscosity oil in which the oil-temperature detection value of the oil before flowing into the oil filter 37 is below the predetermined value, the oil is circulated to the control oil channel 90 simultaneously at the drive start of the oil pump 36 to flow the oil into the pressure chamber 369 immediately. Therefore, the pump discharging amount is set smaller than the maximum discharging amount simultaneously at the drive start of the oil pump, resulting in reducing the flow rate of the oil flowing into the oil filter 37 and preventing damage to the oil filter 37.

Note that in the starting control SA, when the oil-temperature detection value detected by the oil temperature detector 92 is below the predetermined value, the valve opening of the oil control valve 49 may be configured to be larger than that when the oil-temperature detection value exceeds the predetermined value.

Moreover, in the starting control SA, after the drive start of the oil pump 36, the control unit 100 may reduce the valve opening of the oil control valve 49, for example, as the oil-temperature detection value of the oil temperature detector 92 increases, to decrease the oil flow rate of the control oil channel 90 and, thus, the flow rate of the oil flowing into the oil filter 37 is increased. Thus, the oil flow rate to the oil filter 37 is increased as the oil temperature increases, while preventing damage to the oil filter 37, and the oil is supplied to the hydraulic path 50 downstream of the oil filter 37.

[Control Flow of Hydraulic System]

FIG. 9 illustrates a control flow of the hydraulic system 1 according to this embodiment.

First, the ON signal of the ignition switch at a startup of the engine 2, which is detected by the IG-ON/OFF detector 105, is read (51).

Next, the oil-temperature detection value of the oil temperature detector 92 disposed in the first oil channel 93 is read (S2).

It is determined whether the oil-temperature detection value is below the predetermined value (S3).

If the oil-temperature detection value is below the predetermined value, the starting control SA comprised of the following Steps S4-S7 is executed.

That is, the valve opening of the oil control valve 49 is determined based on the oil-temperature detection value (S4), and the oil control valve 49 is operated (S5). Thus, the oil is now able to flow into the pressure chamber 369, and the oil discharging amount of the oil pump 36 is controlled to be less than the maximum discharging amount.

Then, the drive of the oil pump 36 is started.

The main gallery oil-pressure detection value of the oil-pressure sensor 70 disposed in the main gallery 54 is then read (S6), and it is determined whether the main gallery oil-pressure detection value of the oil-pressure sensor 70 is above the predetermined value (S7).

If the main gallery oil-pressure detection value is determined to be above the predetermined value, since it is confirmed that the oil pressure has been applied to the end of the oil supply channel H of the engine 2, the starting control SA is ended and the normal control SB is resumed (S8).

On the other hand, if the main gallery oil-pressure detection value is not above the predetermined value (i.e., below the predetermined value) at S7, since the oil pressure has not been applied to the end of the oil supply channel H of the engine 2, the starting control SA of Steps S4-S7 is repeated until the main gallery oil-pressure detection value is determined to be above the predetermined value.

Since the predetermined value of the main gallery oil-pressure detection value varies depending on the engine model, such as a length of the oil supply channel H, a value obtained beforehand from experiments etc. is stored as the predetermined value in the memory 100 d of the control unit 100, and the determination is made by comparing the main gallery oil-pressure detection value detected by the oil-pressure sensor 70 with the predetermined value. Note that instead of the determination of whether the main gallery oil-pressure detection value is above the predetermined value, the determination may be made by, for example, a predetermined period of time or more passes while the main gallery oil-pressure detection value ranging within about 10% from the predetermined value (i.e., the detection value becomes substantially constant and stable).

Then, in the normal control SB, the operating state of the engine 2 is read (S9), the target oil pressure which is the control target of the oil control valve 49 is determined based on the operating state (S10), and the valve opening of the oil control valve 49 is controlled so that the oil pressure detected by the corresponding oil-pressure sensor on the hydraulic path 50 reaches the target oil pressure (S11).

Note that at Step S3, if determined that the oil-temperature detection value exceeds the predetermined value, the starting control SA is not performed, but the normal control SB of Steps S9-S11 is performed after the drive start of the oil pump 36.

Then, the normal control SB of S9-S11 is repeated until the OFF signal of the ignition switch accompanying a stop of the engine 2 is detected by the IG-ON/OFF detector 105.

<Operations and Effects of Features of Hydraulic System>

FIG. 10 illustrates a change with time of the oil pressure upstream of the oil filter 37, a change with time of the engine speed which correlates to the oil-pump rotational speed, and a change with time of the oil-pressure detection value of the oil-pressure sensor 70 disposed in the main gallery 54, when the engine 2 is cranked to start and reaches in an idle operating state, i.e., a state where the engine speed reaches about 800 rpm (a value which is set so that the engine does not stall) without stepping on the accelerator and maintained at this engine speed. Note that in the graph, a point P indicates a timing at which the engine speed reaches about 800 rpm (i.e., a timing of the completion of the engine start or the end of cranking). Moreover, a point Q indicates a timing at which the oil pressure of the main gallery 54 reaches a minimum oil pressure required for the lubricating parts (e.g., the crank journals and the cam journals).

As illustrated by a dashed line in FIG. 10, as for the conventional hydraulic system illustrated in FIG. 13, a so-called “spike oil pressure” occurs upstream of the oil filter 37, in which the oil pressure sharply increases when the oil pump 36 starts driving at an engine start. The spike oil pressure is caused at a timing of the oil-pump drive start at the engine start, by the oil being low temperature and high viscosity, and if such a large quantity of the low-temperature, high-viscosity oil flows into the oil filter 37, the oil filter 37 may be damaged. Therefore, the leak passage is conventionally provided upstream of the oil filter 37 and the oil pressure is reduced by leaking excessive oil to the oil pan 6 to protect the oil filter 37.

According to the configuration of this embodiment, as illustrated by a solid line in FIG. 10, an increase in the oil pressure upstream of the oil filter 37 can be observed at the oil pump 36 starting driving; however, the sharp increase in the oil pressure like the spike oil pressure is not observed. Therefore, by the control of the valve opening of the oil control valve 49 of the starting control SA, the oil flow rate into the oil filter 37 is reduced by increasing the oil flow rate of the control oil channel 90 to prevent the damage to the oil filter 37.

As illustrated in FIG. 10, a rise of the oil pressure of the main gallery 54 is slower than a rise of the oil pressure upstream of the oil filter 37 according to a distance of the main gallery 54 separated from the oil pump 36. It can be seen that the oil pressure upstream of the oil filter 37 is stabilized at a substantially constant value at the timing of the point Q at which the oil pressure reaches the minimum oil pressure required for the lubricating parts.

Therefore, according to this configuration, at the timing of the detection value of the oil-pressure sensor 70 disposed in the main gallery 54 reaching the predetermined value (i.e., the oil pressure at the point Q illustrated in FIG. 10), the detection value is configured to be determined YES at Step S7 illustrated in FIG. 9 to resume the normal control SB from the starting control SA. Thus, between the engine startup and the detection value reaching a predetermined main gallery oil-pressure detection value, the damage to the oil filter 37 is controlled by performing the starting control SA, and after reaching the predetermined oil-pressure detection value, the control is switched to the normal control SB of the oil pump 36 to efficiently control the oil pressure of the hydraulic path 50.

Moreover, by this configuration, a downsizing of the hydraulic system 1 is achieved by integrally forming the control oil channel 90 and the oil control valve 49 with the housing 361 of the oil pump 36. Moreover, since the oil channel length of the control oil channel 90 is shorter than the case where the control oil channel 90 is formed in other engine parts, channel flow resistance of the oil channel is reduced. In addition, since the discharging amount is controllable to a further lower quantity even with the valve opening of the electromagnetic control valve being unchanged by increasing the oil pressure of the pressure chamber 369, the pump work is reduced. Further, since the excessive oil is directly introducible into the pressure chamber 369 of the oil pump 36 without being leaked to the oil pan 6 by connecting the control oil channel 90 to the pressure chamber 369 of the oil pump 36 through the oil control valve 49, the pump work is reduced.

Second Embodiment

Below, other embodiments according to this disclosure are described in detail. Note that in description of these embodiments, the same reference characters denote the same components as the first embodiment and thus, detailed description thereof is omitted.

In the first embodiment, the control unit 100 performs the starting control SA based on the oil-temperature detection value detected by the oil temperature detector 92. On the other hand, in this embodiment the control unit 100 estimates the viscosity of the oil based on the oil-temperature detection value, and then performs the starting control SA based on the estimated viscosity value of the oil. The control unit 100 stores beforehand viscosity characteristics of the oil (a relation of the viscosity to the oil temperature) in the memory 100 d.

As illustrated in FIG. 11, the operation part of the control unit 100 then estimates the viscosity of the oil based on the oil-temperature detection value detected by the oil temperature detector 92 and the viscosity characteristics stored in the memory 100 d to obtain the estimated viscosity value (S31).

Next, the control unit 100 determines whether the estimated viscosity value obtained by the operation part is above a predetermined value (S32).

If the estimated viscosity value is above the predetermined value, the control unit 100 executes the starting control SA, and on the other hand, if the estimated viscosity value is below the predetermined value, the control unit 100 executes the normal control SB without executing the starting control SA.

According to this configuration, the temperature of the oil before flowing into the oil filter 37 is detected, and the viscosity of the oil is estimated based on the detected oil-temperature detection value and the viscosity characteristics of the oil stored beforehand in the memory 100 d. If the estimated viscosity value is a high viscosity above the predetermined value, the oil flow rate of the control oil channel 90 is increased above the predetermined quantity, and the flow rate of the oil flowing into the oil filter 37 is reduced. Therefore, damage to the oil filter 37 is prevented.

Third Embodiment

In the first and second embodiments, the starting control SA is performed if the oil-temperature detection value detected by the oil temperature detector 92 is below the predetermined value.

On the other hand, instead of using the oil temperature, the temperature of the coolant (or water) in a water jacket (water-cooled part; not illustrated) formed around the cylinder head 4 of the engine 2 illustrated in FIG. 1 may be used as temperature of fluid which contacts the components of the vehicle.

That is, when the ambient temperature is at an extremely low temperature where the starting control SA is required, it is considered that the temperature of the coolant in the water jacket is also low, and under such a circumstance, the oil viscosity is also relatively high.

Thus, for example, a coolant temperature detector is configured to detect the temperature of the coolant in the water jacket, and if the coolant temperature detected by the coolant temperature detector is below a predetermined value (e.g., 0° C. or lower), or if the estimated viscosity value which is estimated based on the ambient temperature is above the predetermined value, the starting control SA is performed. On the other hand, if the coolant temperature exceeds the predetermined value, or if the estimated viscosity value is below the predetermined value, the normal control SB is performed without performing the starting control SA.

Fourth Embodiment

In the third embodiment, the temperature of the coolant in the water jacket is used as the temperature of the fluid which contacts the components of the vehicle. Alternatively, temperature of air outside the vehicle (i.e., the ambient temperature), which contacts exterior components of the vehicle (e.g., a vehicle door) may be used.

Specifically, an ambient temperature detector is provided to the vehicle door, etc. to detect the ambient temperature, and if the detected ambient temperature is below the predetermined value (e.g., 0° C. or lower), or if the estimated viscosity value which is estimated based on the ambient temperature is above the predetermined value, the starting control SA is performed. On the other hand, if the detected ambient temperature exceeds the predetermined value, or if the estimated viscosity value is below the predetermined value, the normal control SB is performed without performing the starting control SA.

Fifth Embodiment

In the above embodiments, the temperature of the fluid which contacts the components of the vehicle is detected, and if the detected fluid temperature is below the predetermined value, the starting control SA is performed.

Alternatively, as illustrated in FIG. 12, without detecting the temperature of the fluid which contacts the components of the vehicle, if the ON signal of the ignition switch is detected by the IG-ON/OFF detector 105, the starting control SA is performed before the oil pump 36 starts driving.

In this configuration, the starting control SA is forcibly performed when the oil pump 36 starts driving at a startup of the engine 2. Therefore, it is unnecessary to provide the fluid temperature detector on the components of the vehicle, and the damage to the oil filter 37 is effectively controlled with a simple configuration.

Sixth Embodiment

In the above embodiments, at Step S7 illustrated in FIGS. 9, 11, and 12, the starting control SA is performed until the oil-pressure detection value of the main gallery 54 detected by the oil-pressure sensor 70 becomes above the predetermined value, and the normal control SB is triggered to be resumed when the oil pressure of the main gallery 54 becomes above the predetermined value.

As for the trigger of switching from the starting control SA to the normal control SB, as illustrated in FIG. 10, the end timing of cranking (i.e., the point P) at which the engine speed detected by the engine speed detector 102 (engine speed detection value) reaches the predetermined engine speed (e.g., 800 rpm) may be used. The normal control SB may then be resumed when the detected engine speed becomes above the predetermined engine speed.

Alternatively, a timing at which an accelerator pedal is stepped on (i.e., a timing at which the accelerator valve opening detected by the accelerator opening detector 103 illustrated in FIG. 2 becomes above a predetermined value) may also be used as the trigger.

Alternatively, the signal detected by the gear detector 104 may also be used as the trigger.

Alternatively, a timer control may also be used so that the control is switched from the starting control SA to the normal control SB after a predetermined period of time passes from the timing at which the oil pump starts driving at an engine startup.

Seventh Embodiment

In the above embodiments, the starting control SA is configured to make the valve opening of the oil control valve 49 more than the predetermined rate so that the oil is able to circulate in the control oil channel 90.

Alternatively, in the starting control SA, the valve opening of the oil control valve 49 may be set at the maximum (fully opened) so that the oil flow rate of the control oil channel 90 becomes the maximum. Specifically, for example, the starting control SA may fully open the oil control valve 49 at Steps S4 and S5 in FIGS. 9, 11, and 12, and then maintain the fully-opened state until the starting control SA is ended. By this simple configuration, damage to the oil filter 37 is prevented.

Other Embodiments

Note that in the first embodiment, although the control oil channel 90 and the oil control valve 49 are integrally formed with the housing 361, they may be formed as separated components and then attached to the housing 361. Therefore, they are easily attachable to various types of oil pumps other than the oil pump 36.

Moreover, the engine 2 is not limited to the in-line four-cylinder gasoline engine, but may be any kind of engine. For example, the engine may be a diesel engine.

It should be understood that the embodiments herein are illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof, are therefore intended to be embraced by the claims.

DESCRIPTION OF REFERENCE CHARACTERS

-   1 Hydraulic System (Oil Feeding Device) -   2 Engine -   4 Cylinder Head -   36 Oil Pump -   37 Oil Filter -   49 Oil Control Valve (Control Valve) -   50 Hydraulic Path -   51 Second Oil Channel -   52 Third Oil Channel -   54 Main Gallery -   54 b Branched Point -   60 Head Gallery -   70 Oil-Pressure Sensor (Oil-Pressure Detector) -   90 Control Oil Channel -   90 a Upstream Control Oil Channel -   90 b Downstream Control Oil Channel -   92 Oil Temperature Detector (Fluid Temperature Detector) -   93 First Oil Channel (Pump Downstream Oil Channel) -   100 Control Unit (Controller) -   100 b Operation Part (Estimator) -   100 d Memory -   105 IG-ON/OFF Detector (Starting Demand Detector) -   361 Housing (Pump Housing) -   361 b Discharge Passage (Pump Downstream Oil Channel) -   365 Pump Chamber (Operating Chamber) -   369 Pressure Chamber (Control Oil-Pressure Chamber) -   H Oil Supply Channel 

What is claimed is:
 1. An engine oil feeding device, comprising: a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof; an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump; an oil filter disposed in the oil supply channel, the oil supply channel including: a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter; and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump; and a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by changing a valve opening thereof, wherein a starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate before the oil pump starts driving and set smaller than the predetermined rate after the oil pump starts driving.
 2. The engine oil feeding device of claim 1, wherein the valve opening of the control valve is set to the maximum rate in the starting control.
 3. The engine oil feeding device of claim 1, wherein: the oil pump is provided with a pump housing accommodating the operating chamber and having a discharge port for discharging the oil from the operating chamber, the pump downstream oil channel is provided in the pump housing and having a discharge passage connecting the operating chamber with the discharge port, the control oil channel is branched from the discharge passage, and the control oil channel and the control valve are integrally formed with the pump housing.
 4. The engine oil feeding device of claim 1, wherein: the oil supply channel has a hydraulic path communicating with a downstream side of the oil filter, and connected with the oil fed part, the engine oil feeding device further comprises an oil-pressure detector for detecting an oil pressure of the hydraulic path, and in a case where a detection value of the oil-pressure detector becomes above a predetermined value during the starting control, the control of the control valve is switched to a feedback control in which the valve opening of the control valve is adjusted so that the oil pressure of the hydraulic path becomes a target oil pressure that is determined according to an operating state of the engine.
 5. The engine oil feeding device of claim 1, wherein: the oil supply channel has a hydraulic path communicating with a downstream side of the oil filter, and connected with the oil fed part, the engine oil feeding device further comprises an engine speed detector for detecting an engine speed of the engine, and in a case where an engine speed detection value detected by the engine speed detector becomes greater than a predetermined engine speed during the starting control, the control of the control valve is switched to a feedback control in which the valve opening of the control valve is adjusted so that an oil pressure of the hydraulic path becomes a target oil pressure.
 6. An engine oil feeding device, comprising: a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof; an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump; an oil filter disposed downstream of the operating chamber of the oil pump in the oil supply channel, the oil supply channel including: a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter; and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump; a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by a valve opening thereof being changed; and a fluid temperature detector mounted to one of the engine and a component of a vehicle to which the engine is mounted, and for detecting temperature of fluid that contacts one of the engine and the component, wherein a starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate when a fluid temperature detection value detected by the fluid temperature detector is below a predetermined value before the oil pump starts driving and the valve opening is set smaller than the predetermined rate after the oil pump starts driving.
 7. The engine oil feeding device of claim 2, wherein: the fluid is an oil flowing through the pump downstream oil channel, and the fluid temperature detector detects an oil temperature.
 8. The engine oil feeding device of claim 2, wherein: the fluid is a coolant that flows in a water-cooled part of the engine, and the fluid temperature detector detects a coolant temperature of the coolant in the water-cooled part.
 9. The engine oil feeding device of claim 2, wherein: the fluid is air outside of the vehicle, and the fluid temperature detector detects an ambient temperature outside the vehicle.
 10. An engine oil feeding device, comprising: a variable-displacement oil pump having an operating chamber and a control oil-pressure chamber, and for changing a capacity of the operating chamber according to a pressure of the control oil-pressure chamber to change a discharging amount thereof; an oil supply channel communicating with the operating chamber of the oil pump, and coupled to an oil fed part provided downstream of the oil pump; an oil filter disposed downstream of the operating chamber of the oil pump in the oil supply channel, the oil supply channel including: a pump downstream oil channel connecting the operating chamber of the oil pump with the oil filter; and a control oil channel branched from the pump downstream oil channel and coupled to the control oil-pressure chamber of the oil pump; a control valve provided in the control oil channel, for changing an oil flow rate of the control oil channel by a valve opening thereof being changed; and a fluid temperature detector mounted to one of the engine and a component of a vehicle to which the engine is mounted, for detecting temperature of fluid that contacts one of the engine and the component, wherein a starting control is performed in which the valve opening of the control valve is set larger than a predetermined rate when an estimated viscosity value estimated based on a fluid temperature detection value detected by the fluid temperature detector is above a predetermined value before the oil pump starts driving, and the valve opening is set smaller than the predetermined rate after the oil pump starts driving. 